#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<vector>
using namespace std;

class Solution
{
public:
    vector<vector<int>> generate(int numRows)
    {
        vector<vector<int>> vv(numRows);
        for (size_t i = 0; i < numRows; i++)
        {
            vv[i].resize(i + 1, 0);
            vv[i].front() = vv[i].back() = 1;
            // == vv[i][0] = vv[i][vv[i].size() - 1] = 1;
        }

        for (size_t i = 2; i < vv.size(); i++)
        {
            for (size_t j = 1; j < vv[i].size()-1; j++)
            {
                vv[i][j] = vv[i - 1][j] + vv[i - 1][j - 1];
            }
        }


        return vv;
    }
};